1. Field of the Invention
The invention relates to a lancet device, an adjusting front mechanism for use on a lancet device, and a method of using a lancet device. In particular, the invention includes a lancet device which utilizes an adjustable tip or front. Lancet devices are used to penetrate and puncture the skin in order to allow the taking of a blood sample for testing. The device allows the user to control the depth of this penetration by a simple adjustment mechanism.
2. Discussion of Background Information
Lancet devices are commonly used to prick the skin of the user so that one or more drops of blood may be extracted for testing. Some users such as diabetics, for example, may have to test their blood sugar levels several times a day. This may be accomplished by the user using a simple needle. However, this procedure is often problematic for the user since the needle may be difficult to handle. Moreover, controlling the depth of penetration cannot be reliably accomplished without the use of a mechanical device. Additionally, many users simply cannot perform the procedure owing to either a fear of needles or because they lack a steady hand. As a result, lancet devices have been developed which allow the user to more easily and reliably perform this procedure.
Presently, most lancet devices lack convenient and flexible adjustability. Such devices are typically made adjustable by switching their tips. U.S. Pat. No. Re. 32,922 to LEVIN et al. is one such device. That is, the user must remove one tip having a set depth and replace it with another having a different set depth. This, of course, creates the problem of storing the replaceable tips, which if not properly done, may result in their misplacement, damage, contamination, or the like.
An improved device would allow the user to more easily adjust the depth of penetration and would overcome some of the disadvantages described above. Moreover, since the skin thickness can vary slightly from user to user and finger to finger, a need exists for efficiently adapting the depth of penetration. For example, an index finger may be more calloused than a middle finger, and the more calloused finger will typically have a thicker skin. By adjusting the depth of puncture so that the depth is no greater than necessary for extracting a required amount of blood, any pain experienced by the user may be minimized.
Lancets having an adjustable tip are known per se. For example, U.S. Pat. No. 4,469,110 to SLAMA discloses a mechanism which adjusts the penetration depth by rotating a threaded sleeve relative to a body. The SLAMA device is characterized as a “single bottom” device which employs a threaded design which can be expensive to manufacture. Moreover, such a device may require the user to rotate the threaded sleeve up to 360 degrees and more in order to attain the proper depth setting. Further, such a threaded resign is prone to inadvertent setting changes since there is nothing but frictional engagement between the mating threads to maintain the adjustment setting.
U.S. Pat. No. 4,895,147 to BODICKY et al. functions in a similar manner to the device in SLAMA and therefore suffers from similar disadvantages.
U.S. Pat. Nos. 5,464,418 and 5,797,942 and 5,908,434 to SCHRAGA also disclose similar lancet devices and are hereby incorporated herein by reference as though set forth in full herein.
As disclosed in U.S. Pat. No. 5,908,434, the lancet device has a body portion which encloses a lancet and a lancet firing mechanism. The lancet typically has a needle extending therefrom and is caused to move towards the tip of the device by a trigger or firing mechanism. The lancet device forces the needle, by virtue of the needle being fixed thereto, out of the device by some distance or depth so that the needle can penetrate the skin of the user. The function of this firing mechanism and the lancet body design is disclosed in each of U.S. Pat. Nos. 5,797,942 and 5,908,434. These patents are incorporated by reference herein in their entirety and are therefore only briefly discussed herein.
What is needed is a front cap or tip design which can accurately and precisely control the depth of penetration of the needle relative to the surface of the user's skin. The front cap forms the tip portion of the lancet device. It uses an adjustment sleeve which resembles a nut and which is rotatable by the user. The nut has circumferential grooves and projections which help the user to grip it with his fingers. The nut is rotatable with respect to the front cap and/or the lancet body. Located on the inside the front cap is disposed a stop cap which is moveable in at least two directions. The stop cap can move forwards and backwards in the direction of the movement of the lancet and needle. Moreover, the stop cap can also rotate.
Thus, while advances have been made, there is a continuing need for a lancet device which provides for convenient and reliable adjustment of penetration depth.